ci: add Gitea Actions workflow for test validation

- Runs on PRs targeting main and pushes to main
- Uses oven-sh/setup-bun@v2 to provision Bun
- Runs bun test v1.3.12 (700fc117) to validate the library

.gitea/workflows/validate.yml

@@ -0,0 +1,25 @@
+name: Validate
+
+on:
+  push:
+    branches: [main]
+  pull_request:
+    branches: [main]
+
+jobs:
+  test:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Setup Bun
+        uses: oven-sh/setup-bun@v2
+        with:
+          bun-version: latest
+
+      - name: Install dependencies
+        run: bun install
+
+      - name: Run tests
+        run: bun test